Microphone question - K3
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I want to replace the element in a Kenwood MC-50 with an electret. I know that the K3 provides bias voltage to pin 1 on the front mic connector which is also the audio line - as long as bias is selected in the mic sel menu. Does this pin already have the coupling capacitor in line or do I need to add that in the microphone? I don't see a capacitor or resistor inside my MH2 hand mic so I'm assuming all I have to do is connect the audio and bias leads to pin 1 and the ground to pin 7?
Thanks all for the help! 73 Bill NZ0T |
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> I want to replace the element in a Kenwood MC-50 with an electret. I know
> that the K3 provides bias voltage to pin 1 on the front mic connector which > is also the audio line - as long as bias is selected in the mic sel menu. > Does this pin already have the coupling capacitor in line Yes. 73, Lyle KK7P _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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I tried a RS electret element I have here and the audio is distorted and weak - do I have a bad element or am I doing something wrong? I wired the element directly to the mic wires bypassing the transformer in the mic with no cap or resistor. The red wire and audio to pin 1 and the ground to pin 7. Guess I'm clueless when it comes to electret mics!
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Are you saying that you connected 2 wires to pin 1? There normally
should only be one wire to pin 1, and that is the AF line which should connect the other end direct to the + side of the electret element. The other side of the electret element must connect to ground (pin 7 or pin 8). Turn bias ON in the FP mic menu and likely with an electret, you can use the L setting. In other words, the MIC SEL menu parameter should be FP.L bIAS. 73, Don W3FPR NZ0T wrote: > I tried a RS electret element I have here and the audio is distorted and weak > - do I have a bad element or am I doing something wrong? I wired the > element directly to the mic wires bypassing the transformer in the mic with > no cap or resistor. The red wire and audio to pin 1 and the ground to pin > 7. Guess I'm clueless when it comes to electret mics! > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Forgive me for being dense about this! The RS element has a red wire that is the V+ for the element. The other wire is the shielded audio output wire. Because the K# has switchable voltage available at pin 1 and from what Lyle posted I assume a coupling capacitor (which allows both V+ and audio to coexist?) in that line my understanding was that the red V+ wire and the audio output wire both go to pin 1 and the shield to pin 7. If I connect the audio output to pin 1 and the shield to pin 7 where do I connect the red V+ wire to get the voltage needed to power the element?
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You are correct that with a 3 lead electret - the V+ and the AF should
both be corrected to pin 1. The remaining pin of the mic element should connect to pin 7 or pin 8. Many electret elements only have 2 leads and must obtain the bias voltage through the AF line, apparently the one you have provides for separate powering. With a 3 lead electret element, you could try connecting only the AF pin of the element to pin 1, and the ground to pin 7 or 8, and connect the V+ wire through a 10k resistor to pin 5. If you wire it that way, you do not need the bias turned on (but it may not matter whether bias is on or off). 73, Don W3FPR NZ0T wrote: > Forgive me for being dense about this! The RS element has a red wire that is > the V+ for the element. The other wire is the shielded audio output wire. > Because the K# has switchable voltage available at pin 1 and from what Lyle > posted I assume a coupling capacitor (which allows both V+ and audio to > coexist?) in that line my understanding was that the red V+ wire and the > audio output wire both go to pin 1 and the shield to pin 7. If I connect > the audio output to pin 1 and the shield to pin 7 where do I connect the red > V+ wire to get the voltage needed to power the element? > > > Don Wilhelm-4 wrote: > >> Are you saying that you connected 2 wires to pin 1? There normally >> should only be one wire to pin 1, and that is the AF line which should >> connect the other end direct to the + side of the electret element. The >> other side of the electret element must connect to ground (pin 7 or pin >> 8). >> Turn bias ON in the FP mic menu and likely with an electret, you can use >> the L setting. In other words, the MIC SEL menu parameter should be >> FP.L bIAS. >> >> 73, >> Don W3FPR >> >> NZ0T wrote: >> >>> I tried a RS electret element I have here and the audio is distorted and >>> weak >>> - do I have a bad element or am I doing something wrong? I wired the >>> element directly to the mic wires bypassing the transformer in the mic >>> with >>> no cap or resistor. The red wire and audio to pin 1 and the ground to >>> pin >>> 7. Guess I'm clueless when it comes to electret mics! >>> >>> >>> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> >> >> > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.9.19/1860 - Release Date: 12/21/2008 3:08 PM > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by NZ0T
The Radio Shack electret elements can be used to make a very effective (and
cheap) microphone. I've used them a number of times, as have many others. Perhaps you did get a bad one, but that's easy enough to verify by simply trying another one--they only cost a couple of bucks. One thing though, you need to house the element in a proper way. I don't know how you are doing it, but hopefully you are mounting the element is a good microphone housing of some sort. However, I'm confused by your wiring description. You should only need to make one connection to pin 1--the microphone lead. The K3 applies the bias based on the internal settings you make through the menu. Dave W7AQK ----- Original Message ----- From: "NZ0T" <[hidden email]> To: <[hidden email]> Sent: Monday, December 22, 2008 5:56 AM Subject: Re: [Elecraft] Microphone question - K3 > > I tried a RS electret element I have here and the audio is distorted and > weak > - do I have a bad element or am I doing something wrong? I wired the > element directly to the mic wires bypassing the transformer in the mic > with > no cap or resistor. The red wire and audio to pin 1 and the ground to pin > 7. Guess I'm clueless when it comes to electret mics! _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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It turns out the element I had was bad. I bought a couple today and it turns out RS has 3 different electret elements. The one I had has 3 wires which makes it easier to use an outboard bias supply. They also have a PC mount one with 2 leads and one with 2 wire leads. I used the 2 wire lead one (red wire to pin 1 and black to pin 7) and it sounds fine to me with the monitor. I'll get on air reports tonight with the usual group on 1.947. Believe me, they will let me know if it sounds bad.
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